Abrasive blasting wheels and vanes



Oct. 24, 1967 J. E. BOWLING, JR 3,348,339

ABRASIVE BLASTING WHEELS AND VANES Filed May 24, 1965 2 ShetsSheet 1H'VVENTOR JOSfiplZlSiBOtUZiififm ATTORNEYS Oc 1967 J. E. BOWLING. JR

ABRASIVE BLASTING WHEELS AND VANES 2 Sheets-Sheet 2 Filed May 24, 1965INVENTOR ATTORNEYS United States Patent g 3,348,339 ABRASIVE BLASTINGWHEELS VANES Joseph E. Bowling, Jr., Waynesboro, Pa., assignor to ThePangborn Corporation, Hagerstown, Mi, a corporation of Delaware FiledMay 24, 1965, Ser. No. 458,150 3 Claims. (Cl. 51-9) ABSTRACT OF THEDISCLOSURE A rotatable abrasive blasting wheel assembly includes aplurality of abrasive propelling vanes radially mounted on a rotatablewheel. The vanes alternately tilt forward and backward with respect tothe wheel surface and include flared discharge ends so that theresulting blast pattern has a uniform distribution of abrasive particlesover a substantially wider area than the width of each vane.

This application is a continuation-in-part of my application Ser. No.400,527, filed Sept. 30, 1964, now abandoned.

This invention relates to an abrading apparatus and more particularly toan apparatus for widening the abrasive blast stream of abrasive blastingwheels.

In many abrasive operations it is desirable to use as wide and extensivean abrasive blasting pattern as possible. For instance, wide blastingpatterns are most desirable when treating strip or sheet metal such assheet steel. The use of wide blast patterns reduces the number of blastwheels required for such an operation.

One of the most serious problems encountered in blasting flat workpiecessuch as sheets and coils with present blasting methods is the problem ofsuper-saturation of the blast stream at high, for example 100horsepower, flows of abrasive. This problem is especially serious withthe smaller sizes of abrasive, for example abrasive shot having anaverage particle size of 0.007 inch in diameter. Such small sizeabrasive is very desirable in for example descaling stainless steelbecause of the relatively light surface indentations it produces priorto cold reduction.

Super-saturation occurs, in essence, because the number of particles inthe blast stream at a given time increases as the cube of the reductionin particle diameter while the space per particle in the stream areaincreases only as a square function of the diameter. Whensuper-saturation occurs many of the particles are constrained fromstriking the workpiece and instead collide with each other thus reducingthe blast efficiency proportionately.

Various means have heretofore been proposed for reducing the density ofthe blast stream. Some success for example has been attained by use ofvarious configurations of openings in the impeller case of the abrasiveblasting wheel which controls the manner in which the particles exudefrom the impeller area. This method however causes the density to bereduced by stretching the blast pattern longitudinally, and it istherefore limited to use with relatively wide workpieces since the mostpractical and economical way of blasting other than very narrow work iswith the blast pattern normal to the direction of work travel.Mechanical and feeding limitations have made it impractical to reducethe density of the pattern of blast by merely widening the vanes and thefeeding parts suchas the impeller and impeller case.

Another method which has been somewhat effective is that described inPatent No. 2,983,082. This method depends totally upon causing theabrasive particles to rebound out of the path of the incoming particlesWhile actually concentrating the particles each wave thus 3,348,339Patented Oct. 24, 1967 however tending to produce interference betweenparticles in the same wave. This factor is increasingly important whenblasting with very small particles. A further method is described inPatent No. 3,242,615, dated Mar. 29, 1966 in which means are describedfor Widening the blast stream.

It is therefore one objective of the present invention to provide a newand novel blast assembly wherein wider abrasive blast patterns areachieved than with former abrasive blast wheels.

Another object of the invention is to provide a new and novel rotatableblasting wheel assembly wherein the abrasive throwing vanes are flaredat their discharge end with the vanes alternately tilted with respect tothe surface of the blasting wheel.

Other objects and advantages of the invention will become more apparentfrom a study of the following description and drawings wherein:

FIG. 1 is a side view of the rotatable blast wheel assembly of thepresent invention;

FIG. 1a is a View similar to FIG. 1 in a different phase of operation;

FIG. 1b schematically shows the total effect of the blast streams shownin FIGS. 1 and 1a;

FIG. 2 is a plan view of a portion of the rotatable blast wheel assemblyshown in FIG. 1;

FIG. 3 is a side elevation of a backwardly tilted vane or blade used inthe assembly of FIGS. 1-2;

FIG. 4 is a top view of the blade shown in FIG. 3;

FIG. 5 is an end view of the blade shown in FIGS. 3-4;

FIG. 6 is a bottom view of the blade shown in FIGS. 3-5;

FIG. 7 is a side elevation of a forwardly tilted vane or blade used inthe assembly of FIGS. 1-2;

FIG. 8 is a top view of the blade shown in FIG. 7; and

FIG. 9 is an end view of the blade shown in FIGS. 7-8.

This invention overcomes the limitations of prior devices as describedabove by spreading the blast pattern in width rather than in lengthwithout at the same time changing the width of the feeding elements.This is accomplished by having the vanes canted or tilted alternatelyforward and backward, and at the same time by flaring the outer ordischarge ends of the vanes in the direction of particle flow. Thismethod causes the alternate particle -waves to strike the workpiece in aside-by-side attitude from the stream; the present device effectivelyuses lesser volume and lesser horsepower.

It has been demonstrated by tests that the present method of applyingthe blast allows eflicient use of 40% greater abrasive particle flows.For example, tests run on stainless steel coils with very small abrasiveparticles (0.007

inch in diameter) showed that, whereas with conventional blastingmethods super-saturation and ineflicient blasting occurred at 6870 H.P.abrasive loading, the method of this invention allowed eflicientblasting i.e.

. proportionate increase in work travel, up through a flow of HP. Thismeans that where it formerly would require, for example twelve blastingunits on the blast machine to meet production requirements, it is nowpos- 3 sible to build the blast machine with only eight blast units witha consequent reduction in capital investment of about one-third.Accordingly, whereas supersaturation has a detrimental effect on priorarrangements at about 68 HR, it is eliminated as a problem with thepresent arrangement even at 100 HP.

Referring now to the drawing a rotatable blast wheel assembly is shownin FIGS. 1 and 2 which includes a blast wheel 1 having vane supportingchannels 3 for supporting alternately tilted or canted vanes 5 and 7.The vanes 5 and 7 are held in channels 3 by, for example, suitablelocking pins 9 which fit into the channels 3 and the cutouts 11 in thedovetail base 13 of the vanes 5 and 7. Channels 3 are for example 2 /4inches wide at their widest point to receive vanes 5 and 7 which areslightly less than 2% inches wide at their widest point.

An indent 14 (see FIGS. 3 and 7) in the base 13 of the vane houses apressure spring which rests on the floor of the vane channel 3. Thespring (not shown) urges the blades or vanes 5 and 7 upwardly to give agood tight fit of the base walls of the vane against the channel wallsin the wheel 1.

Vanes 5 and 7 are fed abrasive particles which are introduced into spout30 into impeller cage 32 and through slot 34 in the impeller cage.

The abrasive propelling face 15 of the backwardly inclined vane 7 isbest shown in FIG. 3. A strengthening rib 17 is formed at the end of theface 15 of the vane. This provides reinforced strength for the vaneduring its rotation and operation. The vane has an outer extending edgeor flange 19 at the upper edge thereof by which an open trough orchannel is formed with the face 15 along which the abrasive flows. Asclearly shown in FIG. 3 the discharge or outer end of each vane 7 isflared by inclining the upper edge 19 outwardly away from the surface ofwheel 1.

FIG. 4 is a top view of vane 7 having its face 15 tilted away thedirection of rotation of the wheel 1. In other words vane 7 has anegative slant with its discharge face 15 being inclined at an obtuseangle of, for example, about 6 with respect to the outer surface ofwheel 1. The inclination is best shown in FIG. 5 which indicates thedegree of slant of discharge face 15 by reference to the center line 27of vane 7 which is perpendicular to the outer surface of wheel 1.

FIG. 7 best shows abrasive propelling face 16 of the forwardly inclinedvane or blade 5. A strengthening rib 17 and an upper flange are alsoprovided on vane 5. Unlike vane 7, the upper flange 2.0 of vane 5 isparallel to the surface of throwing wheel 1. The lower edge 22, however,is inclined toward throwing wheel 1 thus causing the discharge end ofvane 5 to be flared.

FIGS. 8 and 9 similarly show vane 5 which slants toward the direction ofrotation of wheel 1 or in other words has a positive slant with itsdischarge face 16 being inclined at an acute angle, of for example,about 6 with respect to the outer surface of wheel 1. The extent ofslant is also indicated in FIG. 9 by reference to the center line 27.

FIG. 1 illustrates the resultant "blasting pattern with alternatelycanted vanes 5 and 7, each having oppositely flared discharge ends. Asshown in FIG. 1 the workpiece 21, for example, a stainless steel coil,travels from right to left. The resultant widened blasting pattern isclearly apparent from FIGS. 1, la and 1b. As shown in FIG. 1a, stream S,of the forward canted vanes 5 moves along lowered flared edge 22,strikes work piece 20, and ricochets away from the line of travel of theincoming waves. Correspondingly as shown in FIG. 1, stream s from thebackward canted vanes 7 moves along upper flared edge 19 and alsorichochets away from the line of an incoming wave after striking workpiece 20. Thus the blasting pat: tern width is greatly increased, asshown in FIG. 112, over the blasting pattern of a conventional blastingassembly while at the same time, drastically reducing the streamdensity.

The feed elements for the tilted vanes are most clearly shown in FIG. 1.As indicated therein abrasive particles. are fed into spout 30 to theimpeller which includes irripeller vanes 34 and impeller cage 36 havinga slot 35. The width of the abrasive flow path is, of course, the widthof slot 35. With the aforedescribed arrangement it is only necessary forthe extreme end of the tilted vanes to be flared to clear the abrasiveflow path. Accordingly, flared edge 22 of forwardly canted vane 5 issubstantially in line with one end of slot 35, while flared edge 19 ofbackwardly inclined vane 7 is substantially in line with the other endof slot 35. As clearly indicated in FIG. 1b the combined blasting elfectfrom vanes 5 and 7 is a widened symmetrical pattern.

Obviously, many modifications and variations of the present inventionare possible in the light of the above teachings. It is, therefore, tobe understood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. A rotatable abrasive blasting wheel assembly comprising a rotatablewheel, said wheel having a surface perpendicular to the axis of rotationof said wheel, abrasive propelling vanes secured to said wheel, each ofsaid vanes having a lower edge disposed against said wheel, said loweredge being parallel to said surface from its inner edge near the centerof said wheel to the periphery of said wheel, each of said vanes havinga planar abrasive propelling face with a feed end near the center ofsaid wheel and a discharge end near the periphery of said wheel, saiddischarge end of each face being flared outwardly relative to saidsurface and with respect to said feed end, the abrasive propelling faceof every other vane being forwardly inclined at an acute angle withrespect to said surface, and the abrasive propelling face of theintervening vanes being backwardly inclined at an obtuse angle withrespect to said surface.

2. An abrasive propelling vane for use in rotatable blasting wheelassemblies, said vane comprising a base support with a planar supportingsurface, a feed end, a discharge end, a planar abrasive propel-ling facebetween said feed end and said discharge end, a first flange on saidabrasive propelling face remote from said surface, a second flange onsaid abrasive propelling face adjacent said surface, said second flangebeing parallel to said surface, said first flange terminating at thedischarge end in a flared portion which is inclined toward said surface,and said abrasive propelling face being tilted forward out ofperpendicular alignment with said surface.

3. An abrasive propelling vane for use in rotatable blasting wheelassemblies said v-ane comprising a base support with a planar supportingsurface, a feed end, a discharge end, a planar abrasive propelling facebetween said feed end and said discharge end, a first flange on saidabrasive propelling face remote from said surface, a second flange onsaid abrasive propelling face adjacent said surface, said second flangebeing parallel to said surface, said first flange terminating at thedischarge end in a flared portion which is inclined away from saidsurface, and said abrasive propelling face being tilted backward out ofperpendicular alignment with'said surface.

References Cited UNITED STATES PATENTS 469,642 2/1892 Nehr 519 2,077,6374/1937 Minich 519 2,314,069 3 1943 Blount 51-9 2,983,082 5/1961 Gossard51--9 3,242,615 3/ 1966 Physioc 5 l9 LESTER M. SWINGLE, PrimaryExaminer.

1. A ROTATABLE ABRASIVE BLASTING WHEEL ASSEMBLY COMPRISING IN AROTATABLE WHEEL, SAID WHEEL HAVING A SURFACE PERPENDICULAR TO THE AXISOF ROTATION OF SAID WHEEL, ABRASIVE PROPELLING VANES SECURED TO SAIDWHEEL, EACH OF SAID VANES HAVING A LOWER EDGE DISPOSED AGAINST SAIDWHEEL, SAID LOWER EDGE BEING PARALLEL TO SAID SURFACE FROM ITS INNEREDGE NEAR THE CENTER OF SAID WHEEL TO THE PERIPHERY OF SAID WHEEL, EACHOF SAID VANES HAVING A PLANAR ABRASIVE PROPELLING FACE WITH A FEED ENDNEAR THE CENTER OF SAID WHEEL AND A DISCHARGE END NEAR THE PERIPHERY OFSAID WHEEL, SAID DISCHARGE END OF EACH FACE BEING FLARED OUTWARDLYRELATIVE TO SAID SURFACE AND WITH RESPECT TO SAID FEED END, THE ABRASIVEPROPELLING FACE OF EVERY OTHER VANE BEING FORWARDLY INCLINED AT AN ACUTEANGLE WITH RESPECT TO SAID SURFACE, AND THE ABRASIVE PROPELLING FACE OFTHE INTERVENING VANES BEING BACKWARDLY INCLINED AT AN OBTUSE ANGLE WITHRESPECT TO SAID SURFACE.